/*
 * #%L
 * Alfresco Repository
 * %%
 * Copyright (C) 2005 - 2016 Alfresco Software Limited
 * %%
 * This file is part of the Alfresco software. 
 * If the software was purchased under a paid Alfresco license, the terms of 
 * the paid license agreement will prevail.  Otherwise, the software is 
 * provided under the following open source license terms:
 * 
 * Alfresco is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * Alfresco is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with Alfresco. If not, see <http://www.gnu.org/licenses/>.
 * #L%
 */
package org.alfresco.repo.solr;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock.WriteLock;

import org.apache.commons.codec.EncoderException;
import org.apache.commons.codec.net.URLCodec;
import org.apache.commons.httpclient.HttpClient;
import org.quartz.CronScheduleBuilder;
import org.quartz.JobBuilder;
import org.quartz.JobDataMap;
import org.quartz.JobDetail;
import org.quartz.JobKey;
import org.quartz.Scheduler;
import org.quartz.SchedulerException;
import org.quartz.Trigger;
import org.quartz.TriggerBuilder;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ApplicationEventPublisherAware;

import org.alfresco.error.AlfrescoRuntimeException;
import org.alfresco.repo.index.shard.ShardRegistry;
import org.alfresco.repo.search.QueryParserException;
import org.alfresco.repo.search.impl.JSONAPIResult;
import org.alfresco.repo.search.impl.JSONAPIResultFactory;
import org.alfresco.repo.search.impl.solr.AbstractSolrAdminHTTPClient;
import org.alfresco.repo.search.impl.solr.ExplicitSolrStoreMappingWrapper;
import org.alfresco.repo.search.impl.solr.SolrActionStatusResult;
import org.alfresco.repo.search.impl.solr.SolrAdminClientInterface;
import org.alfresco.repo.search.impl.solr.SolrClientUtil;
import org.alfresco.repo.search.impl.solr.SolrCommandBackupResult;
import org.alfresco.repo.search.impl.solr.SolrStoreMapping;
import org.alfresco.repo.search.impl.solr.SolrStoreMappingWrapper;
import org.alfresco.service.cmr.repository.StoreRef;

/**
 * Provides an interface to the Solr admin APIs, used by the Alfresco Enterprise JMX layer. Also tracks whether Solr is available, sending Spring events when its availability changes.
 * 
 * @since 4.0
 *
 */
public class SOLRAdminClient extends AbstractSolrAdminHTTPClient
        implements ApplicationEventPublisherAware, DisposableBean, SolrAdminClientInterface
{

    private String solrPingCronExpression;
    private String baseUrl;

    private ApplicationEventPublisher applicationEventPublisher;
    private SolrTracker solrTracker;

    private Scheduler scheduler;

    private List<SolrStoreMapping> storeMappings;

    private HashMap<StoreRef, SolrStoreMappingWrapper> mappingLookup = new HashMap<>();

    private BeanFactory beanFactory;

    private ShardRegistry shardRegistry;

    private boolean useDynamicShardRegistration;

    public SOLRAdminClient()
    {}

    @Override
    public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher)
    {
        this.applicationEventPublisher = applicationEventPublisher;
    }

    public void setSolrPingCronExpression(String solrPingCronExpression)
    {
        this.solrPingCronExpression = solrPingCronExpression;
    }

    public void setBaseUrl(String baseUrl)
    {
        this.baseUrl = baseUrl;
    }

    /**
     * @param scheduler
     *            the scheduler to set
     */
    public void setScheduler(Scheduler scheduler)
    {
        this.scheduler = scheduler;
    }

    /**
     * SOLR properties identified by store like "alfresco" or "archive"
     * 
     * @param storeMappings
     */
    public void setStoreMappings(List<SolrStoreMapping> storeMappings)
    {
        this.storeMappings = storeMappings;
    }

    /* (non-Javadoc)
     * 
     * @see org.springframework.beans.factory.BeanFactoryAware#setBeanFactory(org.springframework.beans.factory.BeanFactory) */
    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException
    {
        this.beanFactory = beanFactory;
    }

    public void setShardRegistry(ShardRegistry shardRegistry)
    {
        this.shardRegistry = shardRegistry;
    }

    public void setUseDynamicShardRegistration(boolean useDynamicShardRegistration)
    {
        this.useDynamicShardRegistration = useDynamicShardRegistration;
    }

    /* (non-Javadoc)
     * 
     * @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet() */
    @Override
    public void afterPropertiesSet() throws Exception
    {
        mappingLookup.clear();
        for (SolrStoreMapping mapping : storeMappings)
        {
            mappingLookup.put(mapping.getStoreRef(), new ExplicitSolrStoreMappingWrapper(mapping, beanFactory));
        }
    }

    public void init()
    {
        this.solrTracker = new SolrTracker(scheduler);
    }

    /* (non-Javadoc)
     * 
     * @see org.alfresco.repo.search.impl.solr.SolrAdminClient#executeAction(org.alfresco.repo.search.impl.solr.SolrAdminClient.ACTION, java.util.Map) */
    @Override
    public JSONAPIResult executeAction(String core, JSONAPIResultFactory.ACTION action, Map<String, String> parameters)
    {

        StoreRef store = StoreRef.STORE_REF_WORKSPACE_SPACESSTORE;
        SolrStoreMappingWrapper mapping = SolrClientUtil.extractMapping(store,
                mappingLookup,
                shardRegistry,
                useDynamicShardRegistration,
                beanFactory);

        HttpClient httpClient = mapping.getHttpClientAndBaseUrl().getFirst();

        StringBuilder url = new StringBuilder();
        url.append(baseUrl);

        if (!url.toString().endsWith("/"))
        {
            url.append("/");
        }
        url.append("admin/cores");

        URLCodec encoder = new URLCodec();
        url.append("?action=" + action);
        parameters.forEach((key, value) -> {
            try
            {
                url.append("&" + key + "=" + encoder.encode(value));
            }
            catch (EncoderException e)
            {
                throw new RuntimeException(e);
            }
        });

        url.append("&alfresco.shards=");
        if (mapping.isSharded())
        {
            url.append(mapping.getShards());
        }
        else
        {
            String solrurl = httpClient.getHostConfiguration().getHostURL() + mapping.getHttpClientAndBaseUrl().getSecond();
            url.append(solrurl);
        }
        if (core != null)
        {
            url.append("&core=" + core);
        }

        try
        {

            return JSONAPIResultFactory.buildActionResult(action, getOperation(httpClient, url.toString()));

        }
        catch (IOException e)
        {
            throw new QueryParserException("action", e);
        }

    }

    /* (non-Javadoc)
     * 
     * @see org.alfresco.repo.search.impl.solr.SolrAdminClient#executeCommand(java.lang.String, org.alfresco.repo.search.impl.solr.SolrAdminClient.HANDLER, org.alfresco.repo.search.impl.solr.SolrAdminClient.COMMAND, java.util.Map) */
    @Override
    public JSONAPIResult executeCommand(String core, JSONAPIResultFactory.HANDLER handler, JSONAPIResultFactory.COMMAND command, Map<String, String> parameters)
    {

        StoreRef store = StoreRef.STORE_REF_WORKSPACE_SPACESSTORE;
        SolrStoreMappingWrapper mapping = SolrClientUtil.extractMapping(store,
                mappingLookup,
                shardRegistry,
                useDynamicShardRegistration,
                beanFactory);

        HttpClient httpClient = mapping.getHttpClientAndBaseUrl().getFirst();

        StringBuilder url = new StringBuilder();
        url.append(baseUrl);

        if (!url.toString().endsWith("/"))
        {
            url.append("/");
        }

        url.append(core + "/" + handler.toString().toLowerCase());

        URLCodec encoder = new URLCodec();
        url.append("?command=" + command.toString().toLowerCase());
        parameters.forEach((key, value) -> {
            try
            {
                url.append("&" + key + "=" + encoder.encode(value));
            }
            catch (EncoderException e)
            {
                throw new RuntimeException(e);
            }
        });

        url.append("&alfresco.shards=");
        if (mapping.isSharded())
        {
            url.append(mapping.getShards());
        }
        else
        {
            String solrurl = httpClient.getHostConfiguration().getHostURL() + mapping.getHttpClientAndBaseUrl().getSecond();
            url.append(solrurl);
        }

        try
        {

            JSONAPIResult response = new SolrCommandBackupResult(getOperation(httpClient, url.toString()));

            if (response.getStatus() != 0)
            {
                solrTracker.setSolrActive(false);
            }

            return response;

        }
        catch (IOException e)
        {
            throw new QueryParserException("action", e);
        }

    }

    public List<String> getRegisteredCores()
    {
        return solrTracker.getRegisteredCores();
    }

    /**
     * Tracks the availability of Solr.
     * 
     * @since 4.0
     *
     */
    class SolrTracker
    {
        private final WriteLock writeLock;
        private boolean solrActive = false;

        private Scheduler scheduler = null;
        private Trigger trigger;

        private List<String> cores;

        SolrTracker(Scheduler scheduler)
        {
            this.scheduler = scheduler;
            ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
            writeLock = lock.writeLock();

            cores = new ArrayList<String>(5);

            setupTimer();
        }

        protected void pingSolr()
        {

            SolrActionStatusResult result = (SolrActionStatusResult) executeAction(null, JSONAPIResultFactory.ACTION.STATUS, JSON_PARAM);

            if (result != null)
            {
                registerCores(result.getCores());
                setSolrActive(true);
            }
            else
            {
                setSolrActive(false);
            }
        }

        void setSolrActive(boolean active)
        {
            boolean statusChanged = false;

            try
            {
                writeLock.lock();
                try
                {
                    if (solrActive != active)
                    {
                        solrActive = active;
                        statusChanged = true;
                    }
                }
                finally
                {
                    writeLock.unlock();
                }

                if (statusChanged)
                {
                    // do this outside the write lock
                    if (solrActive)
                    {
                        stopTimer();
                        applicationEventPublisher.publishEvent(new SolrActiveEvent(this));
                    }
                    else
                    {
                        startTimer();
                        applicationEventPublisher.publishEvent(new SolrInactiveEvent(this));
                    }
                }
            }
            catch (Exception e)
            {
                throw new AlfrescoRuntimeException("", e);
            }
        }

        boolean isSolrActive()
        {
            return solrActive;
        }

        protected void setupTimer()
        {
            try
            {
                final String jobName = "SolrWatcher";
                final String jobGroup = "Solr";

                // If a Quartz job already exists with this name and group then we want to replace it.
                // It is not expected that this will occur during production, but it is possible during automated testing
                // where application contexts could be rebuilt between test cases, leading to multiple creations of
                // equivalent Quartz jobs. Quartz disallows the scheduling of multiple jobs with the same name and group.
                JobDetail existingJob = scheduler.getJobDetail(new JobKey(jobName, jobGroup));
                if (existingJob != null)
                {
                    scheduler.deleteJob(existingJob.getKey());
                }
                JobDataMap jobDataMap = new JobDataMap();
                jobDataMap.put("SOLR_TRACKER", this);
                final JobDetail jobDetail = JobBuilder.newJob()
                        .withIdentity(jobName, jobGroup)
                        .usingJobData(jobDataMap)
                        .ofType(SOLRWatcherJob.class)
                        .build();
                trigger = TriggerBuilder.newTrigger()
                        .withIdentity("rmt")
                        .withSchedule(CronScheduleBuilder.cronSchedule(solrPingCronExpression))
                        .build();
                scheduler.scheduleJob(jobDetail, trigger);
            }
            catch (Exception e)
            {
                throw new AlfrescoRuntimeException("Unable to set up SOLRTracker timer", e);
            }
        }

        protected void startTimer() throws SchedulerException
        {
            scheduler.resumeTrigger(trigger.getKey());
        }

        protected void stopTimer() throws SchedulerException
        {
            scheduler.pauseTrigger(trigger.getKey());
        }

        void registerCores(List<String> cores)
        {
            writeLock.lock();
            try
            {
                this.cores = cores;
            }
            finally
            {
                writeLock.unlock();
            }
        }

        @SuppressWarnings("unchecked")
        List<String> getRegisteredCores()
        {
            writeLock.lock();
            try
            {
                return (cores != null ? cores : Collections.EMPTY_LIST);
            }
            finally
            {
                writeLock.unlock();
            }
        }
    }

    /* (non-Javadoc)
     * 
     * @see org.springframework.beans.factory.DisposableBean#destroy() */
    @Override
    public void destroy() throws Exception
    {
        solrTracker.stopTimer();
    }

}
